Regardless of how the COVID-19 pandemic originated, it’s clear that deadly diseases can spread from animals to humans. A new report from Harvard Law School and New York University shows that we’re not doing enough to prevent a new animal-borne virus from becoming the next global pandemic.
The study, which looked at common types of interactions between animals and humans in 15 countries, including the United States, found dozens of examples where viruses could make the leap. Researchers argued that simple policy changes could dramatically reduce the risk of such disease transitions.
According to Ann Linder, lead author of the report, the focus so far has been too much on limiting damage after a pathogen has already jumped from animals to humans, as Ebola did in 2014, SARS-CoV-2 in late 2019, and bird flu threatens to do.
But pathogens are incredibly small — 10,000 times smaller than the head of a pin, she said — and can be highly contagious. “By the time you realize something is happening, that outbreak could have spread beyond the point where it can be contained.”
Instead, said Linder, associate director of policy and research at the Animal Law & Policy Program at Harvard Law School, “we really need to shift our thinking and our focus to preventive policy. We can’t chase these outbreaks.”
So she and her colleagues have spent the past four years looking for weak spots, areas of animal-human interactions where viruses could potentially jump from one to the other. Unfortunately, they’ve found plenty.
In the United States alone, the report cites the following: the exotic pet trade, live animal markets, harvesting of bat guano, keeping of guinea pigs and ferrets, production of coyote and fox urine, roadside zoos, animal fighting, fur farming, commercial agriculture and many other potentially hazardous environments.
“This is a global problem,” said Dr. W. Ian Lipkin, a professor of epidemiology at Columbia University’s Mailman School of Public Health, who was not involved in the study.
Lipkin has long called for closing wet markets like the one in Wuhan, China, where COVID-19 may have originated, and for stricter safety procedures at scientific research labs, like the one in Wuhan, where some believe the virus that causes COVID-19 may have originated. “Finger-pointing is not productive,” he said.
So-called zoonotic diseases have always existed, such as smallpox, HIV/AIDS and last year’s monkeypox outbreak. But researchers believe they are becoming more common as climate change, urbanization, global travel and other changes increase human-animal interactions.
“The general perception is that the more often these interactions occur, the greater the risk of disease transmission,” said Suresh Kuchipudi, chief of the division of infectious diseases and microbiology at the University of Pittsburgh School of Public Health.
The report points out that these problems are not limited to far-flung countries, said Kuchipudi, who was not involved in the study but reviewed it as an independent scientist. “We always think this has to happen somewhere else in the world,” he said. “We have the same kind of activity in our backyard. The risk exists regardless of geography and cultural practices.”
Industry opposition
Linder said her biggest concerns relate to sectors that are “poorly or not regulated at all.”
The report identifies the U.S. mink industry as one that should be better regulated or even eliminated, as the industry poses a risk to human health and its products are unnecessary luxuries.
Unsurprisingly, the mink industry disagrees with the finding that its sector is unsafe.
Mink farmers are diligent stewards of both public and animal health, said Challis Hobbs, executive director of Fur Commission USA, the organization that represents U.S. mink farmers. Mink are sold through auction houses and must be certified and meet biosecurity standards to enter the market, he said via email.
Hobbs noted that early in the COVID-19 pandemic, U.S. mink farmers contributed at their own expense to the development and delivery of a vaccine to protect mink against the SARS-CoV-2 virus.
In the U.S., mink farms long participated in weekly testing for the SARS-CoV-2 virus, but now they are testing sporadically, Hobbs said.
“We continue to work closely with federal, state and local agencies to take all necessary precautions to protect people and wildlife and prevent the spread of disease,” he said. “We adhere to strict animal welfare and biosecurity standards, as do other livestock industries.”
Simple changes can make a big difference
Lipkin described a research trip to Saudi Arabia to study the transmission of Middle East Respiratory Syndrome (MERS), a SARS-like virus first identified in 2012.
MERS was thought to be transmitted by camels, but no one understood how people in large cities like Riyadh could contract the disease when there were no camels around.
Lipkin visited two slaughterhouses. According to tradition, each began at sunset by slaughtering camels, then cows, then sheep. At one slaughterhouse, the butchers used high-pressure hoses to clean the meat before shrink-wrapping it for sale; at the other, they did not.
Lipkin found extremely high concentrations of viral material on the beef and sheep where no tubing was used. No viral material was found where tubing was used.
Lipkin said he remains concerned about the overuse of antibiotics in livestock farming, increasing the risk that these essential medications won’t work when people need them.
Inexpensive genetic analysis can now be used to quickly test wild or farmed animals to see what pathogens they carry that could pose a risk to humans, he said. People who work closely with animals can also have their blood tested to see if they carry antibodies that indicate they have previously been infected with an animal-borne virus.
Policy changes to reduce risks
The report proposes a handful of policy changes in all 15 countries, spread across Africa, Asia, the Americas, Europe, the Middle East and Australia. They include improved regulation and monitoring of animal markets and their supply chains; enhanced public health protections in livestock farming, wildlife trade and livestock production; and policies that support sustainable agricultural practices.
Kuchipudi said it is a question of balancing food security, economy and animal and human health.
“Can we stop all animal operations?” No, he said. “It’s not a solution and it’s not appropriate.”
But the risks can be reduced, especially if people become aware of them, for example through reports like this one, Kuchipudi said.
He also said known risks should be reduced through procedures such as pasteurizing all milk and dairy products, handling animals carefully and avoiding petting zoos or making sure children wash their hands thoroughly after touching animals and do not kiss them.
Such precautions are also important for the animals, said Kuchipudi, who recalled that many pets have contracted COVID-19 from their human family members.
“We really need to recognize that by protecting our animals, we are protecting our (own) health. And vice versa,” he said. “By protecting our environment, we are also protecting the health of humans and animals. They are almost inseparable.”
Mercy for Animals, an international non-profit animal protection organization, also supports this concept, called One Health.
Mercy for Animals has launched a campaign against the use of “downed pigs” – pigs that are too sick, weak or injured to walk on their own – in the food supply.
Allowing such sick pigs into the food supply and exposing workers to them creates an unnecessary risk to human health, said Frances Chrzan, the organization’s senior federal policy manager.
For example, many government officials are concerned about pigs contracting the bird flu that is circulating in poultry and dairy farms. Pigs are known to be mixing vessels for influenza, allowing the virus to transform from one that only affects animals to one that can also infect humans, as happened during the 2009 swine flu epidemic, said Dr. Walter Sanchez-Suarez, a veterinarian and animal welfare scientist at Mercy for Animals.
“It’s a ticking time bomb because we know that the (bird flu) virus is everywhere and they’re creating the perfect conditions for this zoonotic transmission to actually happen,” he said.
Karen Weintraub can be reached at [email protected].